He’s just one of dozens, if not hundreds, of researchers pretty much getting all the same result - which is that red wine is about the healthiest drink possible for a human (with the possible exception of water). He just was lazy.
As to why it works - well, why should we be able to figure that out, we only spend $2.6T per year on medicine and employ 40,000,000 people in the field?
Or regretfully unethical in his ambitiousness. I fear that this is rampant in biomedical research these days. It's not much different than blood doping etc. in the Tour de France, or steroids in baseball and football. Publish something ‘cool’ and get attention, funding, and perhaps a leadership position. Sad.